The type of surfaces over which a vehicle is ridden significantly affects its capacity and efficiency.
While the riding behavior is one of the most important aspects involved in the concept of most vehicles, the ability to allow interchangeability of parts or to retrofit new components on existing vehicles greatly satisfies the owner of vehicles and represents an interesting market source for vendors of specialized parts destined to vehicles such as All-Terrain vehicles (hereinafter “ATV”), light trucks, jeeps, etc.
Specialized parts for those vehicles include carrying cases, winches, plow assemblies just to name a few. These kits may develop the vehicle's capacity to accomplish other functions, to extend its duration of use throughout the seasons or to allow the use of the vehicle under different riding conditions.
For instance, different riding or traction kits (hereinafter, “traction kits”) are sometime installed to replace the wheels of existing all-terrain vehicles. In principle, the kits should minimize the need to change existing components, must be able to fit on the vehicle without interference and should try to minimize any negative change to the overall riding behavior of the vehicle and comfort of the driver.
However, since most vehicles are not initially designed to be used with these traction kits, the overall behavior and/or characteristics of the vehicle can be affected when equipped with one of these kits. Even though these traction kits generally improve traction and weight distribution, they can alter other characteristics such as steering or power transfer.
For example, some ATVs are specifically designed such that the power and torque are not equally distributed among the front and rear wheels. An example of such a vehicle is the Polaris™ Sportsman™ ATV wherein the front wheels receive 80% of the power that is sent to the rear wheels. In other words, the front wheels do not actively contribute to the propulsion of the vehicle as long as the rear wheels do not spin or slip as to lose 20% of their traction power. In practice, this creates a two wheel drive vehicle that automatically becomes a four wheel drive vehicle when the rear wheels slip or spin beyond a certain threshold. This aspect is really appreciated by the drivers.
However, when equipped with traction kits such as the one disclosed in U.S. Pat. No. 6,006,847, the traction kits replacing the rear wheels rarely “spin” or lose traction since the traction kits improve the traction. Therefore, the front wheels or kits are rarely used to their full capacity and the ATV remains effectively a two “wheel” drive vehicle.
Another problem with traction kits, especially for ATVs, can be the limited width of the vehicles. Indeed, equipped or not with traction kits, the width of ATVs is usually limited to about 52 inches. If the traction kit equipped vehicle is wider, it would not fit into the pickup bed of a standard pickup truck or in some trailers. Moreover, when the vehicles are too wide, they are prohibited in certain trails. This total width limitation thus limits the width of the traction band that can be used with these traction kits.
However, larger and/or longer traction bands could be beneficial since they would provide larger contact areas with the ground, thus distributing the weight of the vehicle over a larger area. The improved weight distribution would create less pressure on the ground and more particularly, on the snow. The vehicle would thus have a lesser tendency to sink in soft terrain and would be more stable.
The installation of traction kits on vehicles and especially ATVs can also affect the steering capabilities of the vehicles. Indeed, the traction band of these traction kits has a much larger contact area with the ground than regular tires. Thus, when these kits replace the front wheels of a vehicle, it might be more difficult to turn the vehicle since the larger contact area creates more friction with the ground.
Therefore, upon installation of these traction kits, some vehicle parameters like steering, weight distribution or vehicle characteristic like width may be affected.
Numerous traction kits have been proposed throughout the years. In “Wheel Mount Track Conversion Assembly” (U.S. Pat. No. 5,607,210 issued on Mar. 4, 1997), Brazier proposes a traction kits to replace the wheels of wheeled vehicles. His system further comprises an anti-torque system that prevents the kit from contacting the vehicle. Though it can be easily mounted on a wheeled vehicle, the system of Brazier does not solve the problems mentioned above.
In “Endless Track Structure for Light Wheeled Vehicle” (U.S. Pat. No. 6,006,847 issued on Dec. 28, 1999), Knight proposes an improved sprocket wheel shaft and idler wheels suspension system.
In “Conversion system for all terrain vehicles” (U.S. Pat. No. 6,095,275 issued on Aug. 1, 2000), Shaw proposes an ATV equipped with conversion kits such as ski assemblies and traction assemblies to replace existing wheels. Although adapting to the existing power system, the conversion system does not provide adjustability means for the weight distribution of the vehicle, such that the ATV's weight is dispersed to the ground surface through the traction and ski assemblies.
In “Track Assembly for All-Terrain Vehicle” (U.S. Pat. No. 6,874,586 issued on Apr. 5, 2005), Boivin et al. disclose a traction kit wherein only a fraction of the traction band is in contact with the surface when this surface is flat.
As we can see, many traction kits have been proposed but yet, none of them have solved the problems mentioned above.
There is therefore a need for a traction assembly which improves riding condition when traction assemblies are used to replace existing wheels on vehicles.